The secret is out since pal Karen Civil posted a video on Twitter, which shows the 30-year-old basketball player get down on one knee and popping the question to the Australian singer, 24.
"Would you marry me?" he bellows at the star, who starts laughing and responds with an enthusiastic "Yes!" Nick chose his 30th birthday party to propose and in the background you can hear the couple's loved ones cheering.
According to New York Daily News, the yellow and white diamond ring is a whopping 10.43 carats and worth around $500,000.
"Nick was very involved in designing the ring," Jason Arasheben, CEO of jewellery store Jason of Beverly Hills, said in a release. "We wanted it to be both a ring of Iggy's dreams and a ring that fits her personal style."
The sportsman had hinted a couple of days ago that he was planning something special; in an interview with People magazine he said he was working on "a big surprise" for Iggy.
Swaggy P celebrated his birthday tonight by popping the question to his girlfriend Iggy! pic.twitter.com/mF3W5eRau2— Karεn Ciѵil (@KarenCivil) June 2, 2015
Nick has been dating the star since November 2013, which she confirmed during a visit on Hot 97 radio last year.
The pair will have even more opportunity to spend quality time together and celebrate, as Iggy has cancelled her The Great Escape Tour.
“I've had a different creative change of heart,” she told Seventeen magazine of the decision. “I want to start totally anew, and if I stayed on my tour, that would mean I wouldn't even be able to start working on that until after Christmas.”